In a wideband code division multiple access (Wideband Code Division Multiple Access, referred to as WCDMA) system, after a permanently online mode is adopted to deal with a growth of the number of user equipments (User Equipment, referred to as UE), a forward access channel (Forward Access Channel, referred to as FACH) bears a large amount of signaling data and part of user plane data. Because a bandwidth of an FACH is limited, congestion is likely to occur on the FACH. When the congestion occurs on the FACH, a user cannot receive a data packet in time, and consequently, the user cannot normally carry out a service.
With respect to the problem, a method for transiting a state of a traffic volume is put forward in the prior art. In the method, when congestion occurs on a FACH, a radio network controller (Radio Network Controller, referred to as RNC) determines whether a size of all data packets cached on the RNC and corresponding to a user equipment exceeds a preset traffic volume threshold; and if exceeds, the user equipment is transited from a CELL_FACH state to a CELL_DCH state. In this way, the data packets corresponding to the user equipment can be sent to the user equipment through a DCH or an HS-DSCH, thereby ensuring that a user normally carries out a service. The transition from the CELL_FACH state to the CELL_DCH state (State Transition from CELL_FACH to CELL_DCH) is generally referred to as F2D.
However, in many application scenarios, for example, when a user establishes a link by using a transport control protocol (Transport Control Protocol, referred to as TCP) in a process of logging in to a network, a domain name server (Domain Name Server, referred to as DNS) is resolved in a process that a user logs in to a network, or a DNS is resolved when a web page is opened or the like, a size of generated data packets is usually small and does not reach a traffic volume threshold required for triggering F2D transition, and consequently, these data packets cannot be delivered to the user in time and the user cannot normally carry out a service.